1. Field of the Invention
The present invention relates to an imaging device, and particularly, to an imaging device capable of simultaneously capturing a plurality of images having different characteristics.
2. Description of the Related Art
Conventionally, an imaging device that includes an imaging optical system 1 including a central optical system (a wide-angle lens) 1a in a central portion and an annular optical system (telescopic lens) 1b in a surrounding portion of the central optical system having different characteristics from the central optical system 1a, which are arranged on the same optical axis, an image sensor 3, and an array lens 2 including a plurality of microlenses (pupil imaging lens) arranged on the incidence surface side of the image sensor 3, which forms a pupil image of the imaging optical system on the image sensor 3 using each microlens, as illustrated in FIG. 15, has been proposed (JP2012-253670A).
In the imaging optical system 1 including the central optical system 1a and the annular optical system 1b, an image plane of the imaging optical system 1 is located on the array lens 2, and the array lens 2 forms a pupil image of the imaging optical system 1 on the image sensor 3.
FIG. 16 illustrates one light reception cell 3a on the image sensor 3, and the pupil image of the imaging optical system 1 that one microlens of the array lens 2 forms on the image sensor 3. This pupil image includes a central pupil image (wide-angle lens component) corresponding to the central optical system 1a, and an annular pupil image (telescopic lens component) corresponding to the annular optical system 1b. 
FIG. 17A shows an example in which 5×5 light reception cells 3a of the image sensor 3 are assigned per microlens.
As illustrated in FIG. 17A, in every group of 5×5 (=25) light reception cells, a central pupil image (wide-angle lens component) is received by the light reception cell in the central portion, and an annular pupil image (telescopic lens component) is received by the light reception cells in the surrounding portion.
In every group of 25 light reception cells, an image signal of one pixel of a wide-angle image is generated from the light reception cell receiving a wide-angle lens component and, similarly, an image signal of one pixel of a telescopic image is generated from the light reception cell receiving a telescopic lens component. Accordingly, a wide-angle image corresponding to the wide-angle lens and a telescopic image corresponding to the telescopic lens are obtained, as illustrated in FIGS. 17B and 17C.
In the example illustrated in FIGS. 17A to 17C, a relationship between the number of light reception cells of the image sensor 3 and the number of pixels of the wide-angle image and the telescopic image obtained from the image sensor 3 is light reception cell number:pixel number (×image number)=25:1 (×2).